The Koonankurish Oath (Leaning Cross Oath) of 1653 is the first recorded mass revolt against the Western colonialism in history. This heroic declaration of independence by the Malankara Christians (also known as Malankara Nazrani’s) was to free itself from the imposition of Western supremacy in matters concerning the Church and its practices.

The Portuguese colonized India using Goa as its headquarters. They brought Roman Catholic priests headed by an Arch Bishop to take over the religious supremacy of the Malankara Orthodox Church.
Those days, the Malankara Nazrani Christians were well established and was following the Marthoma tradition of India. The Portuguese tried to lure the Nazrani’s with both money and positions to come under the reign of the Roman Catholic Church. They mercilessly murdered or exiled some of the Persian Bishops, and stopped the arrival of new Bishops to the Indian region.

Arch Bishop of Goa, Alexio Da Menezes tried to influence and force the Malankara Church head Arch-Deacon Geevarghese of Pakalomattom family to bring the Malankara Church under the control of the Roman Catholic Church. All the Malankara church representatives including Arch-Deacon Geevarughese unanimously refused to do so.
Arch Bishop Menezes used his influence with the Raja (King) of Cochin and summoned a meeting of all the representatives of the Church at Udayamperur. The King threatened that absentees to the meeting would end up having their properties confiscated. Thus the historically significant Udayamperur Synod took place on 20th June 1599 led by Bishop Menezes, the Portuguese governor, higher Government officials, and armed Portuguese soldiers with the full support of the Raja of Cochin. Arch Deacon Geevarghese along with 133 priests 10 deacons and 660 laymen attended. The meeting enforced decrees to accept the faith and traditions of the Roman Catholic Church and the authority of the Pope. The Malankara Nazrani Syrian Christians signed the decrees, as they were afraid of the Portuguese opposition and their own King. They accepted the Roman authority with dissent. The St. Thomas Christian’s east Syrian traditions and liturgy was then replaced by Latin Liturgy and traditions of the Roman Catholic Church.

In 1652, the Persian Catholicos sent Metropolitan Mar Ahatallah from Syria to India. He was however arrested by the Jesuits at Mylapore and handed over to the Portuguese who then put him in a ship at Madras, bound to Goa. Enroute its journey the ship stopped by Cochin. Hearing this 25000 strong Nazrani Christians marched to Cochin Harbour and demanded the release of Mar Ahatallah. The Portuguese pushed the ship off to Goa and on the way drowned the Persian Bishop. Hearing this, thousands of St. Thomas Nazrani’s assembled at Mattanchery church on the 3rd of January 1653 and took an oath under a big cross. Since all the people could not touch the cross simultaneously, they all held onto ropes that were tied to the cross in all directions. They then took the historical oath to break free from the clutches of the Roman supremacy and follow only the Malankara Nazrani traditions as well as obey the Marthoma Arch Deacon Thomas I. The Koonankurish Oath was the first proclamation of independence of the Malankara Orthodox Church and it was the first revolt against the colonial rulers of India. The Koonankurishu Oath preserved the
St. Thomas tradition helping to protect the Malankara Orthodox Church from losing its heritage and long history.